It is not avoidable to meet the topography kept out problems when the new generation weather radar is constructed and usedwe probe into a technology of data interpolation in the extension which was kept out for offsetting the defect of the radar picture products, especially to solve the problem of quantitative measure of the rainfall.We hope it is the example of the radar in Nanjing and Lianyungang that can offer some means for other radar station when the new generation radar is used to observe weather. 